Oil engine



Feb. 13,1940. c, L, UMM'INS `2,190,015

v o n. ENGINE Filed Jan. 29. 1958 (ffelssze @IWW/Niza Patented Feb. 13,194C UNITED STATES PATENT vOFFICE o OIL ENGINE Application January 29,193s, serial No. lsvgss'z 4 Claims.

My invention relates .to oil burning engines of the general type whereinthe fuel is burned by the heat of the air compressed' by the pistonwithin the combustion chamber of the cylinder and is more particularlyconcerned with injection devices for such engines.

The general theory of operation of the present invention is broadlysimilar to that which characterizes the injector constructions disclosedin my United States Letters Patent Nos. 1,561,913 and 1,762,653, asregards the reciprocation of an injecting plunger in a mixing chamberwhich communicates with the combustion space of the cylinder through aplurality of ejection ports.

ld 4During the suction stroke of the piston, air is drawn into thecombustion space and the plunger is slowly withdrawn to permit a chargeof fuel oil to enter the mixing'chamber, While, during the compressionstroke, heated air is driven through the ports into the chamber wherethe oil is entrained and thoroughly mixed. with the air. Near thebeginning of the power stroke, the plunger is forced into the mixingchamber and ejects the mixture into the combustion space.

26 In the foregoing construction, the openings through which the fuelpasses into the mixing chamber are located adjacent the ejection portsto insure a thorough commingling of the fuel and the air entering thechamber through the'ports,

i 30 and the plunger when in fully advanced position is relied upon toseal the fuel openings and thus interrupt the flow of 'fuel into themixing cham- 'ber. In small engines, such as those having a bore ofapproximately four inches and less, the as 'securing of an eiective sealbecomes more dimcult because of the reduced size of the parts involvedand, accordingly,- the limited areas available for sealing purposes. Forexample, in an engine having a bore of 3% inches, the base di- 40 ameterof the conical end of the injecting plunger is about 1% of an inch andthis base subtends an angle ofu about 40 degrees at the pointed end.Accordingly, with an injecting structure as disclosed in the above-notedpatents and assuming an engine size just noted, it is clear` that, ifthe injecting plunger fails to seat accurately for any reason, the fueldelivery opening will not be completely sealed' off and, hence, evenwith the plunger in fully advanced position, some drip may be present atthe ejection ports. This condition will obviously result in a reductionin fuel econ-- omy, carbonization of the ejection ports, crank lcasedilution, and a smoky exhaust.

u It is,`therefore, one object of my invention to,

devisean oil engine having aninjecting device en through the ports tothereby insure a thorough commingling with the heated air.

'I'hese and further objects of my invention will E@ K be set forth inthe following specifications, reference being had to the accompanyingdrawing, and the novel means by which said objects are effectuated willbe definitely pointed out in the claims. i

In the drawing:

Figure 1 is a sectional elevation of a portion of a cylinder of an oilburning engine showing the piston substantially at the end of itscompression stroke, and the relation thereto of the fuel in-V 25 jector,ejection ports and the inlet and exhaust valves; and

Fig. 2 is a fragmentaryrsectional view showing a modied arrangement inwhich the injecting plunger directs the fuel charge towards the ejec-`30 tion-ports.

Referring to Fig. 1, the numeral l0 designates part ofa cylinder headmounted. in the usual manner on the 'top of a cylinder Il which isprovided with a reciprocating piston I2 of a four-@35 cycle engine ofthe Cummins Diesel type, to which, for purpose of illustration, I haveshown the preferred embodiment of my invention applied. The usual airinlet and exhaust valves I3' and H, respectively, are mounted forreciprocat. 40 ing movement on opposite sides of the cylinder axisaccording to the general relationship shown in Fig. 1, although thesevalves may be located in other positions Without disturbing theinventive concept involved; -45

While the injecting device hereinafter described is more particularlyintended for use with a Cummins type of engine, where a separate mixingchamber is employed to precondition the fuel charge by mixing andvaporization with and 5a by a mass of air delivered into the mixingchamber during the compression stroke of the piston,

the invention is not to be considered as limited in this respect sinceit generally comprehends the positive cut-oil' of the fuel supply by theln- 4 f jecting plunger at indicated times during the operation of theengine, and the positive directing of the fuel charges toward theejection ports to insure a thorough commingling of the fuel charge withthe airl which is driven through these ports by the engine piston.

In the form shown in the drawing, the fuel injector comprises a bodymember or plug I5, an injecting plunger I6 having a cylindrical portionI1 which is reciprocably mounted in a central bore I8 in the plug, andwhich is further provided with a conical end I9 that is periodicallymoved into a correspondingly shaped mixing chamber 28 located in acup-shaped member 2| that is secured to the inner or combustion spaceend of the plug I5. The chamber 20 is axially aligned with the bore I8and one or more ejection ports 22 connect the chamber 20 with thecombustion space 23 of the cylinder. When the plunger I6 is moveddownwardly, the fuel charge is forced through the ports 22 into thecombustion space and these ports may belocated and shaped to dischargeany arrangement and shape of spray into this space.

The charge of liquid fuel is led from an external source through apassage 24 provided in the plug I5 and this passage merges into anaxially aligned valve chamber 25, the junction of the passage andchamber forming a valve seat 26 which is normally engaged and thepassage 24 closed by a valve 21. This valve is actuated in a closingdirection by a spring 28, one end of which bears against the head of thevalve and the opposite end against a spider 29 that guides the movementsof the valve and which is seated in the lower end of the chamber 25. Afuel passage 30 leads downwardly from the lower end of the valve chamber25 and terminates in the wall of the central bore I8 at a point suchthat the delivery end of the passage will be uncovered when the plungerI6 is occupying the position shown or some higher elevation.

In describing the manner in which my improved injective device coactswith the remaining portions of the oil engine structure, it will beassumed that the piston I2 has drawn a charge of air into the combustionchamber 23 and that the piston is located at some point below thatillustrated in the drawing, but is moving upwardly on the compressionstroke. It will be further understood that, during the suction stroke ofthe piston, a charge of fuel oil under pressure, established either by agravity head or by a pump, has been forced into the mixing chamber 20.This introduction of th fuel charge is effected by the pressure on thefuel line overcoming the pressure of the spring 28 and it is supplied tothe chamber 20 at a time when the plunger is substantially occupying theposition illustrated in the drawing.

During the compression stroke, the temperature of the air increasesrapidly and air is driven into the mixing chamber` 20 through the ports22 to thoroughly mix with and vaporize the o il therein, as describedmore particularly in the above-noted patents. Shortly before the. pistonreaches top center on its compression stroke, the plunger I6 is drivendownwardly by'an-y -suitable means to eject the entire mixture of fueland air from the chamber 23 into the combustion space.

The delivery end of the fuel passage 30 may be located generally asillustrated, or in other words, so that the fuel charge will be directedtoward the ports 22 to insure a thorough com-A mingling of the chargeand air. This action is also facilitated by the impact of the fuelcharge against the conical surface of the plunger as the latter movestowards the ports. Further, it will be particularly observed that thedelivery end of the passage 30 is remote from the ports 22 and that itis sealed by the cylindrical portion of the plunger during injection.

Any drip which might otherwise occur at the ports 22 is, therefore,completely prevented, while still obtaining such a thoroughness ofmixture and entrainment of the oil with the air that any tendency towardstratification of the mixture in the mixing chamber is avoided.Otherwise, some of the fuel might be forced into the combustion chamberin a liquid state, and this condition would cause momentary highpressures, late combustion of part of the charge, a decrease in power,carbon deposits and an unequal distribution of thecharge in thecombustion chamber. The present construction is entirely free of theforegoing `operating faults and retains the advantage of the structuresdisclosed in the noted patents as regards a thorough pre-conditioning ofthe fuel-air mixture in the mixing chamber.

It will be understood that the spring 28 is sufficiently strong tomaintain the valve 21 closed during the period of the cycle when theplunger is retracted, but the valve is not subjected to fuel pressure.Slow drip of the fuel is thereby prevented during this operaive phase ofthe device.

In Fig, 2 is illustrated a fragmentary view generally similar to thatshown in Fig. 1, but embodying a position of the fuel supply passage 3l,corresponding to the passage 30, that does not direct the fuel chargetowards the ejection ports 32. The securing of this result is attainedby causing the charge to impact against the conical end of the plunger33 which acts as the directing element.

In either of the modifications, it will be partcularly noted that thepointed end of the plunger i6 exercises a directive effect on the 'airforced through the ejection ports such that the air is caused to divideand wash over the surface of the conical end of the plunger, therebyinsuring a better distribution of the air in the mixing chamber andeliminating any possibility of a considerable portion of wet fueladhering to the surface, or of being unmixed with the heated air. Anhomogeneous fuel-air mixture is thus assured.

I claim: -f

1. An injecting device for an oil burning engine comprising-'incombination, a body having a chamberprovided with one or more ejectionports and a passage for supplying the chamber with fuel 'under pressure,and an injecting plunger reciprocable in the body to alternately providefor the delivery of fuel to the chamber and to discharge the fuelthrough the ejection ports, the plunger having a surface located todirect toward the ejection ports the fuel charge issuing from thedelivery port of the passage when the plunger is in retracted positionand another surface for sealing the delivery port during injection.

2. An injecting device for an oil burning engine comprising incombination, a body having a cavity terminating in a conical chamberprovided with one or more ejection ports and a passage for supplying thechamber with fuel under pressure, the delivery port of the passageterminating at the surface of the cavity, and an injecting plungerhaving a portion fitting the cavity and a conical end, the portion beingreciprocable in the cavity to alternately uncover and seal the deliveryport and to discharge the fuel through the ejection ports by the conicalend, the conical end being located substantially opposite the deliveryport when the cavity'iltting portion of the plunger is in uncoveringposition to direct the 5 issuing fuel charge toward the ejection ports.3. An injecting device lfor an oil burning engine of the piston typecomprising a conical mixing chamber having a supply port communicatingwith a source of liquid fuel under pressure y '10 and one or moreejection ports providing communication with the combustion space of theengine cylinder and through which air is forced during the compressionstroke of the piston to mix With'fuel delivered into the chamber, and ani6 injecting plunger having a conical end retractible in the chamber toprovide for the delivery of fuel thereto and advanceable to dischargethe mixture through the ejection ports-into the cylm inder, the surfaceof theconlcalfend being loport toward the ejection ports when theplunger is in retracted position and the ejection ports being located todirect air forced into 'the chamcated to deflect the fuel issuing fromthe supply e ber by the piston against the conical end to distribute thesame.

4. An injecting device for an oil burning engine of the piston typecomprising a body having a chamber provided'with one or more ejectionports and a passage for supplying the chamber with fuel under pressure,the ejection ports pro" vlding communication with the combustion spaceof the engine cylinder and through which air is forced during thecompression stroke of the piston to mix with fuel delivered into thechamber, and an injecting plunger reciprocable in the body toalternately provide for the delivery of fuel to the chamber and todischarge the fuel through the ejection ports, the plunger having asurface located to direct toward the ejection ports the fuel chargeissuing from the delivery port of the passage when the. plunger is inretracted position CLESSIELCUMMINS.

